Well tools



y 7, 1968 J. E. REAGAN 3,381,756

WELL TOOLS Filed Sept. 5, 1965 2 Sheets-Sheet l INVENTOR James E. ReaganBY www Fig.| wd m United States Patent 3,381,756 WELL TOOLS James E.Reagan, Dallas, Tex., assignor to Otis Engineering Corporation, Dallas,Tex., a corporation of Delaware Filed Sept. 3, 1965, Ser. No. 484,791 19Claims. (Cl. 166224) ABSTRACT OF THE DISCLOSURE Selective stagecementing tools having a full opening bore provided with lateral outletpassages providing communication between the bore of the tool and theexterior thereof, and having a valve member restrained in closedposition by shear means, actuated by piston means subjectcd to fluidpressure resisting opening movement of said valve means in addition tosaid shear means, in one case having a confined fluid pressure chargeresisting movement of the piston means and the valve member and inanother case having a pressure area on the piston means exposed topressure exteriorly of the tool for resisting movement of the valvemeans to open position, the outlet passages being closed by closuremembers floated into the lateral flow passages with the cement slurrybeing pumped therethrough. The strength of the shear screws and thepressure force resisting movement of the piston means controlling theopening of the valve to permit flow of cement outwardly through thepassages.

This invention relates to well tools and more particularly relates totools for controlling fluid flow from a flow conduit into a well bore.

It is a particularly important object of the invention to provide afluid flow control device for controlling fluid flow from a flow conduitpositioned within the bore of a a well into the annulus within the wellbore around the conduit.

It is another important object of the invention to provide a fluid flowcontrol device which is connected in a string of casing disposed in awell bore to control the flow of cement slurry from the casing into theannular space within the well bore around the casing.

It is another object of the invention to provide a stage cementing toolwhich is connected in a casing string disposed in a well bore to controlthe displacement of cement slurry from the casing string into an annularspace within the well bore around the casing string.

It is still another object of the invention to provide a stage cementingtool through which cement slurry is displaced when a predetermined fluidpressure is exceeded.

It is still another object of the invention to provide a stage cementingtool which includes a valve? element held in a releasably closedposition by a compressible gas in a charge chamber.

It is another object of the invention to provide a stage cementing tooloperable responsive to a fluid pressure level in excess of the pressureof a charge of compressible gas in a charge chamber of the tool.

It is an additional object of the invention to provide a stage cementingtool including an annular piston type valve member to control fluid flowfrom a central bore through the wall of the tool outwardly.

It is still another object of the invention to provide a stage cementingtool through which fluid flow is initiated by exceeding a predeterminedfluid pressure and tenninated by the seating of ball shaped valveelements deposited in the fluid flowing through the tool against seatsprovided around flow passages through the tool.

It is a still further object of the invention to provide ice a stagecementing tool having a valve system which may be adjusted to an openingpressure correlated with the fluid pressure around the tool.

It is another object of the invention to provide a stage cementing toolhaving a valve system including an annular piston type valve elementwhich is subjected to a pressure differential between the inside andoutside of the tool with the area of the annular piston exposed to thepressure around the tool being greater than the area of the pistonexposed to the pressure within the tool.

It is another object of the invention to provide a stage cementingsystem for use in a well bore which includes a plurality of stagecementing tools each of which is operated in response to 'a differentfluid pressure.

Additional objects and advantages of the invention will be readilyapparent from the reading of the following description of a deviceconstructed in accordance with the invention, and reference to theaccompanying drawings thereof, wherein:

FIGURE 1 is a longitudinal view partially in section and partially inelevation illustrating one embodiment of a stage cementing tool inaccordance with the invention;

FIGURE 2 is a view in section along the line 22 of FIGURE 1;

FIGURE 3 is a fragmentary cut-away view in perspective illustrating oneof the lateral flow ports through the wall of the tool and a portion ofthe longitudinal flow passage system of the tool;

FIGURE 4 is a fragmentary view in perspective and section of the annularvalve member and piston of the tool of FIGURE 1;

FIGURE 5 is a fragmentary view in section showing the annular piston andvalve assembly of the stage cementer illustrated in FIGURE 1 moved to anopen position to permit fluid flow through the tool;

FIGURE 6 is a fragmentary schematic view illustrating a stage cementingsystem including a plurality of the stage cementing tools illustrated inFIGURES 1-4; and,

FIGURE 7 is a fragmentary view in section of an alternate form of valvearrangement which may be used in the stage cementer shown in FIGURE 1.

Referring to FIGURES l4, a stage cementing tool in accordance with theinvention includes a tubular mandrel 21 which is threaded along itsupper and lower end sections 2-2 and 23, respectively, to permitconnection of the tool in a string of fluid conduit such as a wellcasing. The mandrel has a plurality of circumferentially spaced ports 23each of which comprises three sections graduated in size with thesmallest 23a opening into the longitudinal bore 24 of the mandrel whilethe next larger section 23b encircles the sec-tion 23a to receive aresilient washer or diaphragm 25. The diaphragm 25 has a centralaperture 26 which is smaller in diameter than the port section 23a. Anouter and largest section 230 of each port 23 encircles the section 2312to receive a rigid washer or diaphragm retainer suitably secured as bywelding to the mandrel over the diaphragm 25 to hold the diaphragm inposition. The retainer 29 has a central opening 30' which is larger thanthe port section 2311 to permit the diaphragm 25 to flex outwardly toallow passage of the ball valve elements 31 as will be explainedhereinafter.

An annular head 32 is suitable secured, as by welding, around themandrel above the ports 23. The head has an external, annular,downwardly opening recess 34 which receives the upper end section of anupper sleeve 35 held on the head by a plurality of set screws threadedthrough the sleeve into the head. An O-ring 41 disposed in an externalannular recess 42 in the head below the set screws seals between thehead and the sleeve. Below the lower end 32a of the head the sleeve 3-5is spaced apart from the mandrel 21 forming an annular space around themandrel in the sleeve over the radial ports.

An annular body 43 is supported around the mandrel below the ports 23.The body has a plurality of longitudinally extending circumferentiallyspaced bores 44 which communicate at their lower ends with an annularslot 45 opening through the lower end of the body. The upper end of eachof the bores 44 is chamfered providing a seat surface around each bore.A plurality of longitudinal circumferentially spaced fingers 51 extendupwardly from the body 43 with one finger positioned between each pairof adjacent bores 44 as best seen in FIGURE 2. The fingers 51 divide theannular space around the mandrel within the sleeve 35 between the head32 and the body 43 into a plurality of circumferentially spaced chambers52 each of which communicates with a port 23 and a bore 44. The fingers51 are slightly spaced apart along their inner edges 51a from themandrel and at their upper ends 51b are spaced below the lower end 32aof the head 32 so that each chamber 52 communicates with the otherchambers 52 on each side of it. An external annular flange 53a formedaround the body 43 is received between the lower end of the upper sleeve35 and the upper end of a middle sleeve 53 which extends downwardly fromthe body in spaced apart relationship around the mandrel. The sleeves 35and 53 are suitably secured together and to the body 43 by an annularweld at 54 and hold the body 43 against movement. Two Orings 55 are eachdisposed in an external annular recess around the mandrel to sealbetween the mandrel and the body 43.

The middle sleeve 53 is reduced in thickness along a lower end sectionforming a downwardly extending skirt 61 which overlaps an upwardlyextending reduced section forming a skirt 62 on the lower sleeve 63which is fitted in spaced apart concentric relationship around themandrel 21. The sleeves 53 and 63 combine to define the outer walls ofan annular flow chamber 64 and an annular charge cylinder '65. Theannular recess 45 opens into the annular chamber 64 while thecircumferentially spaced ports in the sleeve 53 communicate with theannular chamber. The lower outer sleeve 63 is secured at its lower endto an inner sleeve 71 which is held on the mandrel by an annularretainer ring 72 threaded on the section 23 of the mandrel and heldagainst rotation by the set screw 73. A lower end section of the sleeve63 is received in an upwardly and outwardly opening annular recess 74 ina thickened lower end section 7111 of the sleeve 71 and is suitablysecured to the sleeve 71 by an annular weld 75. The sleeve 71 issubstantially reduced in thickness along a central section to providethe inner wall of the annular cylinder or charge chamber 65. Both thesleeves 71 and 63 are slightly increased in thickness along sections 81and 63a respectively, forming a connecting annular passage ofsubstantially uniform thickness cornmunicating between the annularcylinder 65 and the annular chamber 64. A longitudinal flow passage 81is formed in the lower end section 71a of the sleeve 71 communicatingwith a lateral flow passage 82 which is sealed by a removable plug 83 topermit charge gas to be injected through the passages 82 and 81 into thecylinder.

'An annular valve member is slidably disposed within the annular chamber64 around the mandrel to co-act with the lower end of the body 43 overthe slot 45 to control fluid flow from the slot into the chamber 64. Thevalve member 90 has an annular crown 91 molded of a rubber orrubber-like material to provide a sealing surface on the valve memberfor engagement with the lower end of the body 43 to seal over theopening of the slot 45 into the chamber 64 when the valve member is inthe upper position illustrated in FIGURE 1. The valve member has aplurality of circumferentially spaced laterally extending holes 92through which the material forming the crown flows or is extruded duringthe molding of the crown on the valve member to aid in holding the crownon the member. A plurality of circumferentially spaced ports 93 areformed in the valve member below the crown to equalize the pressurewithin the chamber 64 across the valve member.

A downwardly extending annular piston 94 formed on the valve member 90is fitted in sliding relationship 'between the sleeve sections 63a and81 into the annular cylinder 65. An O-ring 95 in an external annularrecess in the inner sleeve section 81 and an O-ring 101 in the internalannular recess '102 in the outer sleeve section 63a provide seals on theopposite sides of the annular piston. The valve element 90 along withthe integrally formed annular piston are initially held in the upperclosed position, as shown in FIGURE 1, by a plurality of shear screws103 each of which is threaded through, the sleeve 63 into the blind hole10% of the valve member 90. The shear screws hold the valve member 90 inclose-d position during assembly of the tool and provide some protectionagainst accidental opening of the valve until the charge chamber 65 isfilled with gas which provides the major force holding the valve closeduntil the desired pressure is reached in the casing. The screws alsoprovide some protection against accidental valve opening due totransient pressure waves which may develop while building the casingpressure to the desired level for opening the valve.

In operation the stage cementing tool 29 is incorporated in a fluid flowsystem as illustrated in FIGURE 6. The stage cementing tools areconnected in the well casing string which is cemented within the wellbore 111 by forcing cement slurry downwardly from the surface throughthe string of casing and outwardly from the casing through the floatshoe 112 and the cementing tools into the annular space 113 within thewell bore around the casing where the cement is allowed to harden toform a seal between the outer wall of the casing and the wall of thewell bore. Most wells upon completion of drilling remain filled withdrilling fluid which is used during the drilling procedure to wash thecuttings from the well bore, to cool the drill bit, and to maintainpressure on the formations being drilled to minimize the escape offluids from the formations through the well bore to the surface duringthe drilling procedure. To reduce the force of the weight of the stringof casing on the surface well equipment from which the casing issupported and lowered a float shoe 112 is connected on the lower end ofthe casing string to control the flow of drilling fluid into the casingstring as the string is lowered into the well bore. The float shoe is aspecial form of check valve which controls upward flow into the casingwhile permitting fluid within the casing to be displaced from the casingoutwardly through the lower end of the casing string. Suitable floatshoes which may be employed are illustrated and described at pages2176-2178 of the Composite Catalog of Oil Field Equipment and Services,1964-65 Edition, published by World Oil, Houston, Tex. The stagecementing tools 20 are connected in the casing string as the string isrun into the well to position a tool at each desired depth when thecomplete casing string is installed. Stage cementing permits the cementslurry to be more readily placed at the depths within the well bore atwhich it is needed and facilitates obtaining a uniform cement seal alongthe length of the casing which is to be cemented. Pumping the cementslurry up the annular space between the casing and the borehole wallfrom the lower end of the casing string is minimized by injection of thecement atidesired depths in the bore hole. Stage cementing isparticularly useful Where zones tend to preferentially take the cementslurry and prevent the build up of the necessary pressure to properlypump the cement up the annulus to the desired height. Frequently thecasing is cemented within the well bore along its lower end sectionwhile the annulus around the casing above such section is left filledwith drilling fluid except in the vicinity of a producing formationwhere the annulus is cemented by use of stage cementing techniques andthe casing and cement are then perforated into the producing formationto allow formation fluid flow into the casing. The cement in the annulusalong the producing formation prevents migration of the formation fluidsupwardly and downwardly in the annulus thus restricting their flow tothe flow paths provided by the perforations through the cement sheathinto the casing.

In planning a stage cementing program a determination is made of thedepth or depths at which cement is to be injected through the casinginto the annulus so that each stage cementing tool may be connected intothe casing string to place it at the proper depth in the Well bore whenthe casing string is run into the well.

Each stage cementing tool to be connected into the casing string isprepared for use at the depth at which it is to be positioned in thewell bore by injecting a compressible fluid such as a gas through theflow passages 82 and 81 into the annular charge cylinder or chamber 65and sealing the charge of gas within the cylinder with the plug 83 whichis threaded into the bore 82. The cylinder 65 is charged to a pressureto provide a force on the piston 94 which in combination with theresistance of the shear screws 103 will hold the annular valve member 90in an upper closed position until the fluid pressure within the casingstring at the cementing tool has been raised to the level at which thecement is to be pumped into the formation. For example, it may bepreferred that the lowest of the cementing tools illustrated in thesystem of FIGURE 6 open to permit cement injection when the pressurewithin the casing at the cementing tool is about 1000 psi. in excess ofthe pressure within the annular space around the casing. If the shearscrews 103 are selected to shear when a pressure of 200 psi. is appliedto the crown 91 through the slot 45, the remaining :force necessary tohold the valve 90 closed until the casing pressure exceeds the annuluspressure by 1000 p.s.i. is

provided by the charge gas in the cylinder 65. The charge chamber ischarged at the surface to a pressure which at the temperature in thewell at the depth the tool is operated will provide the requiredpressure to hold the valve closed. For example, the tool may be chargedat a temperature of 80 deg. F. for use at a temperature of 144 deg. F.and thus the pressure at the time of charging at the surface will besubstantially less than the pressure which will develop in the chamberat the appreciably higher operating temperature. Generally each of thecementing tools used will employ shear screws 103 of the same strengthand thus variations in the opening pressure for each tool is establishedby the pressure of the charge gas in the cylinder 65.

Since the cementing of an annulus Within a well bore around a conduitgenerally begins at the bottom of the well, the stage cementing toolsincorporated in a casing string have opening pressures established atvalues such that the lowest of the tools will open at the lowest fluidpressure with each succeeding tool up the casing string requires ahigher pressure to open it to permit cement slurry to be injected intothe annulus. For example, in the system illustrated in FIGURE 6 thebottom cementing tool may have an opening pressure of 1,000 p.s.i. inexcess of the pressure within the annulus 113; the middle tool may openat a pressure of 1,500 psi. above the annulus pressure; and the top toolmay open at a pressure of 2,000 p.s.i. above the annulus pressure. Eachcementing tool is charged with gas to a pressure at surface temperatureto hold the valve member closed until a predetermined pressure isattained in the casing string at the depth at which the cementing toolwill be operated. Each cementing tool to be used in the casing string isproperly charged and connected into the casing string 110 as the stringis lowered into the well bore.

As the casing string is being lowered into the well bore each cementingtool is connected into the string at a location within the string whichwill position the tool at the desired depth in the well bore when theentire casing string is fully inserted into the well bore to the depthat which it is to be cemented. Generally, a bore hole is already filledwith drilling fluid when a cementing process is begun and as the casingstring with the float shoe 113 on its bottom end is lowered through thefluid filled well bore the float shoe will permit drilling fluid in thebore hole to enter the string of casing at a rate which only partiallyfills the casing so that the casing has suflicient buoyancy to partiallyfloat the casing string and thereby relieve the wellhead supportingapparatus of the full Weight of the string while it is being insertedinto the well bore. When the casing string is at the desired depth inthe well bore it is secured in a suitable conventional manner at thesurface and the procedure of cementing the annulus 113 within the wellbore around the casing string is initiated.

The desired length of the lower end section of the casing string iscemented by pumping a charge of cement slurry downwardly through thecasing string, outwardly through the float shoe 113, and upwardly in theannulus until the desired lower end section of the casing string hasbeen cemented. The slurry is generally displaced through the casingstring and into the well bore by drilling fluid. A suitable wiper orplug element may, if desired, be pumped through the casing between thebody of cement slurry and the displaced drilling fluid to minimizemixture of the two fluids during the pumping process.

When the desired amount of cement slurry has been displaced through thefloat shoe the tubing is suitably plugged at or above the float shoe bya conventional pump down plug element to stop fluid flow from the floatshoe. The slurry is then displaced through the lower stage cementingtool 20 by increasing the pressure within the casing string to the levelrequired to open the valve in the lower cementing tool. The pressurewithin the bore 24 of the tool is applied outwardly through the ports 23and the openings 26 of the diaphragms 25 into the circumferentiallypositioned chambers 52. The pressure is applied from the chambers 52downwardly through the longitudinal bores 4-4- into the annular slot 45against the upper end of the crown 91 on the valve member 90. The forceof the pressure within the slot 45 against the upper end of the crown isopposed by the shear screws 103 and the pressure of the charge fluid inthe cylinder 65. When the pressure acting on the annular area of thecrown exposed to the slot 45 provides a downward force on the crown inexcess of the resistance provided by the shear strength of the screwsand the pressure within the cylinder 65 the screws shear permitting thevalve member to be displaced downwardly with the piston 94 compressingthe gas within the cylinder 65. The valve member and piston movedownwardly with the crown moving away from the opening of the slot 45into the annular chamber 64 permitting cement slurry to flow from thebore 24 of the mandrel 21, through the ports 23 and the diaphragmopenings 26 into the chambers 52, and downwardly through thelongitudinal bores 44 and the slot 45 into the annular chamber 64. Theslurry flows radially outwardly into the annulus 113 through the radialports 70. After the screws 103 are sheared the valve member is biasedtoward the closed position by the gas pressure within the cylinder 65.So long as the pressure within the cement slurry is maintained at avalue suflicient to keep the piston 94 in the downward positioncompressing the gas in the cylinder 65 the valve member remains in theopen position allowing the cement slurry to flow into the annulus. Whenthe quantity of cement to be displaced into the annulus through thelower cementing tool has entered the casing string a plurality of theball elements 31 are deposited in the casing at the surface behind theslurry. Ball elements are selected with a density approximately the sameas the density of the cement slurry so that the ball elements willremain at the desired position in the last of the body of slurry to bedisplaced from the lower tool as the slurry is pumped through the casingstring.

The ball elements may be formed of nylon, rubber, or any other materialwhich is resilient enough to seat on the surfaces 50 to prevent flowinto the passages 44. The ball elements must not be so resilient,however, that they will be extruded through the passages by theoperating pressures in the casing string. At least twice the number ofball elements as the ports 23 may be deposited in the cement slurry inorder to insure that at least one ball element will pass through each ofthe ports. The cement slurry is displaced from the cementing toolthrough the ports 23 until a ball element 31 passes through each of theports 23 into the chambers 52 and downwardly into seated relationshipagainst the surface 50 at the end of each of the longitudinal flowpassages 44. As each ball element passes through the opening 26 in eachdiaphragm 25 the diaphragm is deformed expanding the hole 26 to permitthe ball to pass through the diaphragm and contracting after each ballelement passes through to trap the ball within the chamber 52. A ballelement seats against the upper end of each of the passages 44 toprevent further flow through the cementing tool into the annulus.

Generally the pressure within the cementing tool will be maintained at asuflicient level to prevent any tendency of the cement slurry to backflow into the tool until the cement has set, which may be a period ofseveral hours. If the pressure within the cementing tool is reduced to alevel below the pressure within the charge chamber 65 while the cementis still fluid the valve member 90 is forced by the pressure within thecylinder 65 upwardly to the closed position. While such a pressurereduction is not a normal step in the cementing procedure the pressuremight inadvertently be reduced or an equipment break down might resultin such a pressure reduction. If such a pressure reduction occurs beforethe cement is set the back flow of fluids through the chamber 64, theannular slot 45, and the longitudinal flow passages 44 will unseat theball element 31 at the upper end of each. of the longitudinal flowpassages. Since the opening 26 through each of diaphragms 25 is smallerthan the diameter of the ball elements 31, each ball element is trappedwithin its chamber by the rubber diaphragm and will not normally bedisplaced back through the diaphragm into the bore 24 of the tool withthe minor amount of back flow which might occur during the closing ofthe valve members 90. The ball elements are retained within the flowpaths leading to the longitudinal flow passages 44 so that upon asubsequent increase of the pressure within the cementing tool the ballelements will again be forced against the seat surfaces 50 to preventfluid flow from within the cementing tool outwardly into the annularspace.

If the middle cementing tool is a substantial distance up the casingstring from the lower cementing tool, the cement forced through thelower tool will normally be displaced by drilling fluid which willsubstantially fill the casing to the middle cementing tool. The batch orcharge of cement slurry to be displaced through the middle cementingtool is introduced into the casing at the surface following the drillingfluid used to displace the cement through the lower cementing tool. Whenthe ball elements 31 close the lower cementing tool an increase inpressure will be evident at the surface with the cessation of flowthrough the casing string. At this time the cement slurry to bedisplaced through the middle cementing tool Will have arrived at thetool. The pressure within the casing string is then raised to the levelrequired to open the middle cementing tool. As previously discussed, theopening pressure for the middle cementing tool is established by thepressure of the gas within the cylinder or charge chamber 65 and may be,for example, 500 pounds higher than the opening pressure for the lowercementing tool and 500 pounds below the opening pressure for the uppercementing tool. When the opening pressure for the middle cementing toolis reached within the fluid at the cementing tool the valve element 90of the tool is forced downwardly against the pressure within the chargechamber and the shear screws to shear the screws and compress the chargegas to open the valve and allow the cement slurry to flow into theannular space around the casing string. While the pressure is beingmaintained at the level sufiicient to displace the cement through themiddle cementing tool the lower tool remains in a closed condition dueto the seating of the ball elements 31 on the surfaces 50 at the upperend of the longitudinal flow passages 44 of the tool. Since the pressureat which the middle cementing tool operates is below the operatingpressure for the upper tool the upper tool remains closed. The ballelements 31 are injected into the cement slurry passing through themiddle cementing tool at a position within the stream of slurry whichwill close the flow passages through cementing tool when the desiredamount of slurry has been displaced into the annular space.

The cementing procedure is continued with the pressure within the casingstring being again raised to the level required to open the valve in theupper cementing tool when the step of displacing the slurry through themiddle cementing tool is completed. While the cement is being displacedthrough the upper cementing tool the pressure within the casing stringis appreciably above the operating pressure 'for the middle and lowercementing tools which are maintained in a closed condition by the ballelements 31 in the compartments 52 of each of the tools. When thedesired amount of cement slurry has been displaced through the uppercementing tool the flow through the tool will be shut off by use of theball elements in the same manner as followed with the lower and themiddle cementing tools. The fluid pressure is then maintained in thecasing string at a level sufficient to maintain the ball elements in aseated relationship within the lower, middle, and upper cementing toolsuntil the cement slurry has sufliciently set within the annular space11.3. It may be necessary to hold the pressure Within the casing stringfor a period of several hours to allow for the proper setting of thecement.

The major portion of the cement slurry introduced into the casing stringis preferably displaced from the string through the stage cementingtools and any cement remaining Within the casing string is drilled outpreparatory to completing the well for production by conventionalprocedures. The stage cementing tools are an integral part of the casingstring and thus are cemented in place with the casing string by thecement within the annular space. The cementing tools remain thereforepermanently within the well bore. The cement slurry will set within thevalve mechanism of each of the cementing tools and thereafter preventany fluid flow through the stage cementing tools.

It will now be seen that there has been illustrated and described a newand improved well tool for controlling fluid flow from a conduit into anannular space within a well bore around the conduit.

It will also be seen that there has been illustrated and described a newand improved fluid flow control tool which is operative responsive to apredetermined pressure differential applied across the conduit betweenthe bore of the conduit and the annular space within the well borearound the conduit.

It will now be seen that a new and improved flow control device forcontrolling fluid flow from a flow conduit positioned within the bore ofa well into an annulus within the well bore around the conduit has beenillustrated and described.

It will also be seen that the fluid flow control device is connected ina string of casing disposed in a well bore to control the flow of cementslurry from the casing into the annular space within the well borearound the casing.

It will be further seen that a new and improved stage cementing tool hasbeen illustrated and described for use in a casing string in a well boreto control displacement of cement slurry from the casing into an annularspace within the well bore around the casing.

It will be further seen that the stage cementing tool includes meansoperable responsive to a predetermined fluid pressure for releasingcement slurry through the tool into the annular space around the tool ina well bore.

-It will also be seen that the stage cementing tool includes a valveelement which is releasably held in "a closed position by a compressiblefluid within an annular charge chamber.

It will additionally be seen that the stage cementing tool is operableresponsive to a fluid pressure in excess of a predetermined pressurelevel controlled by a charge of compressible gas in an annularcylindrical charge chamber of the tool.

It will additionally be seen that the stage cementing tool includes anannular piston type valve member to control fluid flow from the bore ofthe tool to the exterior of the tool.

It will be further seen that fluid flow is initiated through thecementing tool when a predetermined fluid pressure is exceeded withinthe tool and the flow is terminated by the seating of a ball shapedvalve element disposed within the fluid flowing through the tool againsteach of the seat surfaces provided at the upper end of each ot" thelongitudinal flow pass-ages through the tool.

It will also be seen that the opening pressure for the tool is adjustedin accordance with the pressure to which the annular cylindrical chargechamber is charged with a compressible fluid.

It will additionally be seen that the annular valve of the tool is heldin a closed position by a combination of the force from the pressurewithin an annular charge chamber and by a plurality of shear screwsreleasably engaged between the slidable valve member and a fixed sleevemember of the tool.

It will also be seen that the major force holding the annular valve inclosed position results from the pressure of the fluid within theannular charge chamber.

It will be seen that there has been described and -illustrated a new andimproved well cementing system including a plurality of stage cementingtools each of which is operable in response to a different tfluidpressure differential applied between the bore of a casing string andthe annular space within a well around the casing string.

It will additionally be seen that each stage cementing tool in thesystem has a different opening pressure as determined by the pressure ofthe fluid in the annular charge chamber.

An alternative form of control valve for use in the stage cementing toolis illustrated in FIGURE 7 wherein components identical to thoseillustrated in FIG- URE 1 are referred to by the same referencenumerals. The annular valve member 90 is slidably positioned within theannular flow chamber 64 and initially held against longitudinal movementby the shear screws 103 extending into the valve member through an outerlower sleeve 130 which, like the sleeve 63 of the tool shown in FIG- URE1, fits in overlapping relationship within the lower end section 61 ofthe sleeve member 53. The inner sur face of the outer sleeve 13!) andthe outer surface of an inner sleeve 131 form an annular cylinder 132around the mandrel. The cylinder 132 communicates to the outside of thelower sleeve through the port 133 which is covered by a porous element134 secured within the recess 135 around the port to keep debris fromentering the cylinder. The sleeve 130 is slightly reduced in thicknessalong a lower section 130a to provide the outer wall of the annularcylinder 132 while the inner sleeve 131 is similarly reduced inthickness along a central section 131a threaded on the upper section tofacilitate assembly and providing the inner wall of the annularcylinder. The inner sleeve is appreciably increased in thickness alongits lower end section 1311; providing an upwardly facing annularshoulder 131c which forms the lower end of the annular cylinder 132. Anupwardly and outwardly opening annular recess 131d is formed around thelower end section of the inner sleeve to receive the lower end sectionof the outer sleeve which is secured on the inner sleeve by the setscrews 136. The sleeves 130 and 131, respectively, are spaced apartalong a section 131e of the inner sleeve and a section 13Gb of the outersleeve providing an annular space 136 connecting the annular flowchamber 64 and the annular cylinder 132. An annular connecting sleeve140 threaded on the valve member 90 is slidably disposed through theannular space 137 connecting the annular valve member with an annularpiston 141 which is slidably disposed within the annular cylinder. AnO-ring 142 within an external annular recess 143 around the inner sleeve131 and an O-ring 144 within an internal annular recess 145 in the outersleeve fonn inner and outer seals, respectively, with the connectingsleeve 140. An internal O-ring within an internal annular recess 151 inthe piston 141 and an outer O-ring 152 within an outer annular recess153 around the piston form inner and outer seals, respectively, with thewalls of the annular cylinder 132.

The assembly including the sleeves 130 and 131 is secured on the mandrelby the retainer ring 72 threaded on the lower end section 23 of themandrel and held against rotation by the set screw 73.

Fluid pressure within the bore 24 tending to open the valve 90 actsdownwardly on an annular area of the crown 91 enclosed between the linesof sealing engagement of the lower end of the body 43 with the crown.The valve 90 is held in the upper closed position by both the shearscrews 103 and the pressure within the annular cylinder 132 below thepiston 141. The pressure within the annular cylinder acts against anannular area of the piston as defined by the lines of sealing engagementbetween the O-rings 150 and 152 with the inner and outer wallsrespectively, of the annular cylinder. The cylinder is exposed throughthe port 133 and the porous member 1334 to the pressure around the tool.In the system of FIGURE 6 the pressure within the annular cylinder isthe same as the pressure within the annulus 113 around the casing stringin the well bore. Thus, the relationship between the sealed area of thevalve crown exposed to the pressure within the bore of the tool mandrelwhen the valve is closed and the sealed area of the annular piston 141determines the required relationship between the pressure within thebore of the tool and the pressure within the annular space around thetool to open the valve 99. For example, in a cementing tool where theeffective sealed area of the piston 141 within the cylinder 132 exceedsby ten percent the effective sealed area of the crown 91 with the lowerend of the annular body 43 around the seal annular slot 45, it isnecessary that the pressure Within the bore of the cementing tool exceedthe pressure within the space around the tool by more than ten percentin order to hold the annular valve in the open position against theannular cylinder pressure. The relationship between the sealed areas ofthe piston and the crown of the valve and the portion of the resistanceto the opening of the valve provided by the shear screws is varied asdesired by the design of each particular cementing tool. It will beobvious, of course, that in order to vary the pressure differentialbetween the bore of the tool and the annulus required for operation ofthe valve it is necessary that the valve design be altered to provide adifferent relationship between the sealed area of the annular piston andthe sealed area of the crown of the valve. Thus, the sizes of the valvecomponents for each valve in a system are dependent upon the depth atwhich the tool is to be used.

A stage cementing system utilizing one or more cementing tools havingthe valve arrangement illustrated in FIGURE 7 is operated in exactly thesame manner as the system previously described with each cementing toolin the system actuated by a predetermined pressure differential betweenthe pressure within the tool and the annulus pressure around the tool.Flow is terminated 1 1 through each tool by the ball valve elementsdisposed in the cement slurry as discussed above.

It will now be seen that there has been described and illustrated a newand novel stage cementing tool utilizing a valve which opens responsiveto a predetermined pres sure relationship between the fluid pressurewithin the bore of the tool and the pressure within the annular spacearound the tool within a well bore.

It will also be seen that the head of the annular valve member of thecementing tool is exposed to the pressure within the bore of the toolwhile the force tending to hold the valve member in closed position isdetermined by a plurality of shear screws and the cross sectional areaof an annular piston exposed within an annular cylinder to the fluidpressure within the space surrounding the tool.

The foregoing description of the invention is explanatory only, andchanges in the details of the construction illustrated may be made bythose skilled in the art, within the scope of the appended claims,without departing from the spirit of the invention.

What is claimed and desired to be secured by Letters Patent is:

1. A tool for controlling fluid flow from a conduit comprising: atubular mandrel adapted to be connected in and become a part of saidconduit, said mandrel having a longitudinal bore therethrough andlateral ports communicating with said bore; body means around saidmandrel providing an annular flow passage between said body means andsaid mandrel communicating with said lateral ports of said mandrel andhaving outlet port means from said annular flow passage opening to theexterior of said body means; an annular seat surface in said annularpassage between said lateral ports and said outlet port means; saidannular seat surface communicating with said lateral ports and saidannular passage; an annular valve member in said annular passage betweensaid seat surface and said outlet port means for engagement with saidannular seat surface to control fluid flow through said passage; meansproviding an annular pressure chamber in said body means below saidoutlet port means; an annular piston opcratively associated with saidannular valve member on the side thereof opposite the seat surface, saidpiston having its end opposite said valve member slidably disposed insaid pressure chamber in sealed relationship therewith; and means forproviding fluid pressure within said annular pressure chamber to act onsaid end of piston to bias said piston and said valve member toward saidannular seat surface; said valve member being movable to open said flowpassage in response to fluid pressure within said tubular mandrel andbeing movable to closed position in response to fluid pressure withinsaid pressure chamber acting on said piston.

2. Apparatus in accordance with claim 1 wherein said means for providingfluid pressure comprises means for injecting a charge of fluid into saidannular chamber and sealing said fluid within said annular chamber tohold said annular valve member at a closed position on said annular seatsurface until the fluid pressure within said bore of said mandrelexceeds a predetermined value.

3. Apparatus in accordance with claim 1 wherein said means for providingfluid pressure comprises flow passage means from said annular chamber incommunication with the space exteriorly of said tool whereby saidannular piston is biased toward said annular valve member by fluidpressure exteriorly of said tool.

4. A stage cementing tool comprising: a tubular mandrel adapted to beconnected in and become a part of a well conduit, said tubular mandrelhaving a plurality of circumferentially spaced radial ports; an annularbody disposed around said mandrel provided with a plurality oflongitudinally extending flow passages and an annular seat surfacearound each of said longitudinal flow passages at the end thereofadjacent to said radial ports adapted to receive a ball valve elementfor preventing fluid flow through each of said flow passages; saidannular body having an annular lower seat surface at the other endthereof opening into said longitudinal flow passages; annular sleevemeans around said mandrel securing said annular body in position andproviding flow passage means communicating said radial ports with saidlongitudinal flow passages in said body; said annular body and saidmandrel providing an annular passageway therebetween communicating withthe annular lower seat surface and with the exterior of the body; anannular valve member slidably positioned in said annular passageway toengage said lower annular scat surface to control fluid flow throughsaid longitudinal flow passages in said annular body; means providing anannular chamber in said sleeve communicating with said annularpassageway; an annular piston slidably disposed in said chamber andconnected with said annular valve member; and means for providing afluid pressure within said annular chamber to bias said annular pistontoward said annular seat surface.

5. A stage cementing tool according to claim 4 wherein said meansproviding a fluid pressure within said annular chamber to bias saidannular piston toward said annular seat surface includes means providedin said sleeve for injecting and sealing a charge of fluid in saidannular chamber.

6. A stage cementing tool according to claim 4 wherein said meansproviding a fluid pressure in said chamber for biasing said pistontoward said seat surface includes means providing fluid communicationfrom said annular chamber to the outside of said tool whereby saidannular piston is biased toward said annular seat surface by thepressure exteriorly of said tool.

7. A stage cementing tool comprising: a tubular mandrel having a boretherethrough adapted to be connected in a well conduit; said mandrelhaving a plurality of circumferentially spaced radial ports; a flexiblediaphragm secured over each of said radial ports, each. said diaphragmhaving a central opening therethrough smaller than said radial port;annular sleeve means secured around and spaced apart from said mandrelproviding flow chambers communicating with said radial ports andproviding an annular cylinder longitudinally spaced along said mandrelfrom said radial ports; annular body means supported around said mandrelwithin said sleeve means, said body being provided with longitudinalflow passages communicating with said flow chambers and with a seatsurface around the end of each of said flow passages adjacent saidradial ports; said annular body means being further provided with anannular opening from said longitudinal flow passages through the otherend of siad body; said annular body means being spaced from said annularcylinder providing an annular flow passage within said sleeve; saidannular sleeve means having a plurality of radial circumferentiallyspaced ports communicating the exterior thereof with said annular flowpassage; an annular valve member sildable within said annular flowpassage adapted to engage said annnlar body means around said annularopening controlling fluid flow from said radial ports, through said flowchambers, said longitudinal flow passages, and said annular slot; and anannular piston slidable in said annular cylinder connected with saidannular valve member, said annular piston being exposed to fluidpressure within said annular cylinder on the side of the piston oppositeto said valve member biasing said annular piston and said annular valvemember toward a closed position in seated relationship against saidannular body means.

8. A stage cementing tool according to claim 7, including means forinjecting a fluid into said annular cylinder and sealing said fluidwithin said cylinder to provide fluid pressure for biasing said annularpiston and said annular valve member toward closed position.

9. A stage cementing tool according to claim 7 including means providingfluid communication from exteriorly of said sleeve means into saidannular cylinder whereby fluid pressure from exteriorly of said sleevemeans acts on 13 the end of said annular piston opposite the valve meansto bias said piston and said valve member toward closed position.

10. A squeeze cementing tool comprising: a tubular mandrel adapted to beconnected within and form a part of a well conduit, said mandrel havinga longitudinal bore therethrough and a plurality of radialcircumferentially spaced ports for lateral displacement of fluid fromsaid bore through said mandrel; annular sleeve means spaced around andspaced apart from said mandrel providing an upper annular space aroundand communicating with said radial ports, an intermediate annular flowchamber, and a lower annular cylinder; an annular body secured withinsaid sleeve means around said mandrel below said radial ports; aplurality of longitudinally extending fingers supported on said annularbody circumferentially spaced around said body, each of said fingersextending between adjacent radial ports dividing said upper annularspace into a plurality of flow chambers, each of said chamberscommunicating with one of said radial ports; said annular body beingfurther provided with a plurality of longitudinally extendingcircumferentially spaced flow passages, each of said flow passagescommunicating with one of said flow chambers; said annular body beingalso provided with a valve seat surface at the end of said body adjacentto said radial ports around each of said longitudinal flow passages toreceive a ball valve element for shutting off fluid flow through each ofsaid longitudinal flow passages; said annular body being also providedwith an annular slot opening through the other end of said body intosaid longitudinal flow passages of said body to communicate said flowpassages with said central annular flow chamber; said sleeve means beingprovided with radial ports opening into said central annular flowchamber; an annular valve member slidably positioned within said centralannular flow chamber adapted for longitudinal movement, the end of saidvalve member adjacent to said annular body being adapted to engage saidbody over said annular slot for controlling fluid flow from saidlongitudinal flow passages into said central annular flow chamber; anannular piston formed on the other end of said annular valve memberextending in sliding relationship into said lower annular cylinderadapted to respond to fluid pressure within said annular cylinder forbiasing said piston toward said annular body to bias said annular valvemember toward closed position; and said sleeve means being provided withmeans for supplying said annular cylinder with fluid pressure to biassaid piston toward said annular body.

11. A stage cementing tool in accordance with claim wherein said meansfor supplying fluid pressure to said annular cylinder comprises flowpassage means and sealing means for charging said annular cylinder onthe side of said piston opposite said valve member with gas underpressure and sealing said gas within said annular cylinder.

12. A stage cementing tool according to claim 10 wherein said means forsupplying fluid pressure to said annular cylinder comprises flow passagemeans communicating said annular cylinder on the side of said pistonopposite said valve member with the space exteriorly of said tool.

13. A stage cementing tool comprising: a tubular mandrel having alongitudinal bore extending therethrough and a plurality ofcircumferentially spaced radial ports, said mandrel being adapted to beconnected in and form a part of a well conduit; an annular head membersecured around said mandrel above said radial ports; an upper sleevesection secured to said head member around and spaced apart from saidmandrel providing an upper annular space around said mandrel within saidsleeve member over said radial ports; an annular body secured with saidupper annular sleeve below said radial ports, said annular body having aplurality of longitudinal circumferentially spaced flow passages, a seatsurface around each of said flow passages at a first end of said bodyadjacent to said radial ports, and an annular slot extending into saidannular body from the second end of said body communicating with saidlongitudinal flow passages; a plurality of longitudinal fingerssupported on said annular body between said body and said annular headmember dividing said annular space around said radial ports into aplurality of circumferentially spaced flow chambers, each of saidchambers communicating with one of said radial ports and with one ofsaid longitudinal flow passages through said annular body; a flexiblediaphragm secured to said mandrel over each of said radial ports, saiddiaphragm having a central opening smaller than said radial portassociated with said diaphragm; a central sleeve secured with said uppersleeve around said mandrel and annular body spaced apart from saidmandrel and having a plurality of radial ports below said annular body;a lower outer sleeve supported below said central sleeve spaced apartfrom said mandrel; a lower inner sleeve around said mandrel within saidlower outer sleeve; a lower portion of said central sleeve and an uppersection of said lowe outer sleeve defining an annular central flowchamber around said mandrel below said annular body; said lower innersleeve and said lower outer sleeve being spaced apart from each otherproviding a lower annular cylinder and an annular space communicatingbetween said cylinder and said central annular flow passage; an annularvalve member slidably disposed within said central flow chamber adaptedto move into and out of engagement with the said second end of saidannular body over said annular slot for controlling fluid flow from saidlongitudinal flow passages through said slot into said central annularflow chamber; an annular piston formed on said annular valve memberextending through said annular space between said central flow chamberand said lower cylinder into said cylinder; seal means supported by saidlower, inner and outer sleeves to seal between said sleeves and saidannular piston; and means provided in said tool for applying fluidpressure within said annular cylinder for biasing said annular pistontoward said annular body.

14. A stage cementing tool in accordance with claim 13 wherein saidmeans for applying fluid pressure in said annular cylinder comprisesmeans for filling said annular cylinder with a charge of gas and sealingsaid charge of gas within said annular cylinder on the side of saidannular piston opposite said valve member.

15. A stage cementing tool in accordance with claim 13 wherein saidannular piston has a lower end section within said annular cylinderhaving a cross-sectional area greater than the portion of said pistonexposed in said annular flow chamber and said means for applying fluidpressure in said annular cylinder comprises flow passage meanscommunicating said annular cylinder on the side of the piston oppositesaid valve member with the exterior of said cementing, whereby fluidpressure from exteriorly of said tool acts on said piston to bias thevalve member toward closed position.

16. A stage cementing tool in accordance with claim 15 wherein thecross-sectional area of said annular piston within said annular cylinderis greater than the crosssectional area of said piston exposed to fluidpressure in said annular flow chamber.

17. A system for displacing cement slurry from a well conduit positionedwithin a well bore into the annular space within said well bore aroundsaid conduit at a plurality of preselected depths comprising: a wellconduit positioned within said well bore; and a plurality of stagecementing tools connected in said conduit spaced apart each from theother along the length of said conduit at selected intervals at whichcement slurry is to be displaced from said conduit, each of saidcementing tools having means providing an annular cylinder in said tooland an annular piston slidably disposed therein; an annular valve memberconnected with said piston and biased toward a closed position by fluidpressure within said annular cylinder acting on said piston and beingactuatable to open said valve member responsive to a predeterminedpressure level 1 5 within said well conduit, each of said cementingtools being so arranged that the annular valve of the tool above thelowest of said tools opens in response to a pressure within said conduitin excess of the pressure required to open the annular valve of thecementing tool immediately therebelow.

18. A stage cementing system as defined in claim 17 wherein the annularcylinder of each of said cementing tools is closed and a charge of gasunder pressure is confined to said cylinder acting on the pistontherein, whereby the valve member in each cementing tool is biasedtoward the closed position by said charge of gas in said sealed annularcylinder.

19. A stage cementing system as defined in claim 17 wherein each of saidcementing tools has means communicating the annular cylinder on the sideof the piston opposite said valve member with the exterior of said toolwhereby fluid pressure from exteriorly of the tool enters the cylinderto act on the piston therein, whereby the valve member in each cementingtool is biased toward a closed position by the fluid pressure within theannular space exteriorly of said tool within the bore hole.

References Cited UNITED STATES PATENTS 1,601,239 9/1926 Crowell137516.15 1,684,551 9/ 1928 Manning 166154 X 1,854,518 4/1932 Little.

2,178,845 11/1939 Baker l66224 X 2,251,977 8/1941 Burt 16626 X 2,374,1694/1945 Boynton 166224 X 2,837,165 6/1958 Roberts 166-224 X 3,010,51411/1961 FOX 16621 3,022,829 2/1962 Hodges 166-224 3,049,759 7/1962Garrett et a1 166-224 3,097,699 7/1963 Orr 166-26 X 3,270,765 9/1966Waters 137155 CHARLES E. OCONNELL, Primary Examiner.

I. A. CALVERT, Assistant Examiner.

